1. Field of the Invention
The present invention relates to a vehicle headlamp, and in particular, to an AFS (Adaptive Front-lighting System) type vehicle headlamp adapted to faithfully change a light illumination direction in accordance with a travelling state of a vehicle.
2. Description of the Related Art
As a vehicle headlamp of such type, for example, as disclosed in Japanese Unexampled Patent Application Publication No. 2010-108867, there is known the one that is configured in such a manner that: a lamp unit incorporating a light source is pivotably supported on a bracket via support shafts that are embedded in a perpendicular direction of the lamp unit; and among the support shafts, a lower side support shaft (hereinafter, referred to as a lower support shaft) is coupled to an actuator.
In addition, the lower support shaft of the lamp unit is configured to be engaged with an output shaft of a swivel motor in the actuator, and the lamp unit is turned in a transverse direction around the support shaft by means of drive of the swivel motor so that a so called swivel operation is made.
Further, among the support shafts of the lamp unit, a support shaft to be embedded on an opposite side of the actuator (hereinafter, referred to as an upper support shaft) is pivotably supported on the bracket via a ball bearing, enabling the actuator to be slid in a forward/backward direction with respect to the bracket by means of drive of a leveling motor in the actuator. In this manner, the lamp unit is turned in a vertical direction around the ball bearing so that a so called leveling operation is made.
Furthermore, as a vehicle headlamp made of such constituent elements, for example, as disclosed in Japanese Unexamined Patent Application Publication No. 2010-049862, there is known the one that is configured in such a manner that a spring member is fixed to a bracket, and by means of the spring member, a tip end of an upper support shaft of a lamp unit is compressed so as to allow the upper support shaft to generate a biasing force along an axial direction of the support shaft. In this manner, the lamp unit is biased to a lower side on which an actuator is to be disposed to thereby preclude a so called backlash from being generated between the lamp unit and the bracket or the actuator.
However, the spring member adapted to compress the tip end of the upper support shaft of the lamp unit is configured by itself, as is evident from Japanese Unexamined Patent Application Publication No. 2010-049862. In other words, this spring member is configured as a member that is independent of a member or the like for holding a bearing of the upper support shaft that is disposed in proximity to the spring member, for example. Therefore, this spring member has entailed insofar an inconvenience such as an increased number of parts.
Moreover, the spring member adapted to compress the tip end of the upper support shaft of the lamp unit has been configured to have a distance between a compression point (a load point) of the spring member and a bracket fixing portion, so that a moment takes place in the spring member, whereby damage to the bracket due to the spring member is likely to occur.
The present invention has been made in view of such a circumstance, and it is an object of the present invention to provide a vehicle headlamp that is capable of forming a spring member adapted to compress a tip end of an upper support shaft of a lamp unit together with a bearing holding portion adapted to hold a bearing of the upper support shaft to thereby prevent an occurrence of damage to a bracket due to the spring member.